Candida albicans is a member of the indigenous human flora and is responsible for the largest percentage of oral and esophageal infection of fungal origin in the AIDS patient. While several putative C. albicans virulence factors have been identified that may contribute to oral candidiasis, efforts to detect others suffer from the inherent problem of utilizing cells prepared in a laboratory environment to distinguish gene products which may only be expressed in an infected host. To circumvent this problem, patterns of C. albicans gene expression have been compared and several genes have been identified that are differentially expressed in comparisons of in vivo vs. in vitro growth. During the course of the present investigation, experiments will be performed to: i) determine the importance of the identified genes in promoting survival and infection in an appropriate animal model, and ii) approach the question as to whether genes deemed important in the animal model play a similar role in colonization and infection of humans. It is anticipated that the results will provide insight concerning C. a/b/cans pathogenesis, as well as to identify new potential targets for antifungal drug discovery.